Fabrication of Porous Aluminum by Spacer Method Consisting of Spark Plasma Sintering and Sodium Chloride Dissolution

Abstract

Porous aluminum with a porosity of 78% and pore size of 850–1000 μm was fabricated under various sintering pressure, sintering time and raw Al powder size conditions by the spacer method consisting of spark plasma sintering (SPS) and sodium chloride (NaCl) dissolution. The effects of the fabrication conditions on compressive properties of the porous Al were investigated. The sintering pressure of 20 MPa and sintering time of 10 min were needed to fabricate robust porous Al under the sintering temperature of 843 K and raw Al powder size of 3 μm. Also, the porous Al specimen fabricated from Al powder of 300 μm exhibited much lower flow stress than those fabricated from Al powder of 3 and 20 μm when employing the temperature of 843 K, the pressure of 20 MPa and the duration time of 10 min. This indicates that the raw Al powder size is needed to be much smaller than the spacer size. This is because the Al particle cannot touch with adjacent Al particles when the Al powder size is comparable to the spacer size.